Go to Showroom > Brands to access the brand landing page and then click on any brand under "Brand Name".
The "Edit Brand" pop-up box will appear. You can edit the brand name and the logo.
Click the blank brand logo to bring up the image uploader pop-up. Browse to find a suitable product picture, and then use the cropping tool to crop it to your liking.
Move the crop box with your mouse and resize it by dragging the corners.
When you're comfortable with how the image looks, press "Save". If you want to start all over, press "Cancel" and start the process over again.
You can also make changes to brand name. When you're all done, click "Save".